chore: scaffold monorepo and migrate uhd_web design system (W0-A)

- pnpm workspace: apps/{web,server}, packages/{contracts,db,domain,adapters,tasks,agent,testkit}
- server: Hono + zod-openapi, API Key auth with scopes, redacting pino logger, SSE event bus with replay, worker heartbeat
- db: Kysely + pg, file migrator, 0001_init (settings/api_key/audit_event/outbox_event)
- web: React Router 7 SPA console shell with 12 workspace placeholders, uhd_web tokens/ui/guard scripts
- docs: ADR-001 (Node over Deno), dev runbook, design system rules

Co-Authored-By: Claude Fable 5.1 <[email protected]>

apps/web/app/api/health.ts

@@ -0,0 +1,13 @@
+import { useQuery } from "@tanstack/react-query";
+import type { HealthStatus } from "@umt/contracts";
+import { apiData, TTL_SECOND } from "~/lib/api";
+
+/** 服务健康状态,15 秒轮询 */
+export function useHealth() {
+  return useQuery({
+    queryKey: ["health"],
+    queryFn: ({ signal }) => apiData<HealthStatus>("/api/v1/health", { signal }),
+    refetchInterval: 15 * TTL_SECOND,
+    retry: false,
+  });
+}